The utility model relates to a digital geothermal logging system of high temperature high pressure, its characterized in that: including the pressure -bearing outer pipe and the heat preservation inner tube of coaxial setting, pressure -bearing outer pipe's one end is closed totally by the instrument lower clutch, and pressure -bearing outer pipe's the other end passes through the instrument top connection and seals, and the one end of heat preservation inner tube is sealed, and the other end passes through the instrument top connection and the temperature sensor joint seals, is provided withmeasurement element in the heat preservation inner tube, and measurement element includes temperature sensor, pressure sensor and naI crystal, photomultiplier. The utility model discloses in, can carry out well temperature well logging, pressure well logging and gamma rays well logging simultaneously, be favorable to more comprehensive measurement each item parameter, and pressure -bearing outer pipe, heat preservation inner tube form an independent seal chamber respectively, to realize inside and outside thermal -insulated separating of heat preservation inner tube smoothly and press, does reliable operating temperature interval reach 10 DEG C - + 250 DEG C, the pressure -bearing reaches 55 MPa, realizes the well logging under high temperature, high -pressure operating mode smoothly.